Synthesis and Conformational Analysis of Pyran Inter-Halide Analogues of D-Talose

Submitting author affiliation:
Université Laval, Quebec, Canada

Beilstein Arch. 2024, 202437.

Published 06 Jun 2024

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This preprint has not been peer-reviewed. When a peer-reviewed version is available, this information will be updated.


In this work, we describe the synthesis of halogenated pyran analogues of D-talose using a halo-divergent strategy from known 1,6-anhydro-2,3-dideoxy-2,3-difluoro-β-D-mannopyranose. In solution and in the solid-state, all analogues adopt standard 4C1-like conformations despite 1,3-diaxial repulsion between the F2 and the C4 halogen. Moreover, the solid-state conformational analysis of halogenated pyrans reveals deviation in the intra-annular torsion angles arising from repulsion between the axial fluorine at C2 and the axial halogen at C4, which increases with the size of the halogen at C4 (F < Cl < Br < I). Crystal packing arrangements of pyran inter-halides show hydrogen bond acceptor and nonbonding interactions for the halogen at C4. Finally, density functional theory (DFT) calculations corroborate the preference of talose analogues to adopt a 4C1-like conformation and a natural bonding orbital (NBO) analysis demonstrates the effects of hyperconjugation from C-F antibonding orbitals.

Keywords: pyran inter-halide, organofluorine, solution-state conformation, solid-state conformation

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When a peer-reviewed version of this preprint is available, this information will be updated in the information box above. If no peer-reviewed version is available, please cite this preprint using the following information:

Lessard, O.; Grosset-Magagne, M.; Johnson, P. A.; Giguère, D. Beilstein Arch. 2024, 202437. doi:10.3762/bxiv.2024.37.v1

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